generating equal diagonal lines in PIL

Question

What I'm trying to do is generate equal diagonal lines in PIL. What I'm doing is first making a horizontal equally square and then rotating it 45 degrees. But when I'm rotating it the lines aren't big enough, there shouldn't be any black and still be equal. It also should work with more colors

code:

import random

im = Image.new('RGB', (1000, 1000), (255, 255, 255))
draw = ImageDraw.Draw(im)
colors = [(255,0,255), (0,0,255)]
random.shuffle(colors)
length = len(colors)
amount = 1000 / length
x1 = 0
y1 = 0
x2 = 1000
y2 = 0
for color in colors:
    shape = [(x1, y1 + amount // 2), (x2, y2 + amount // 2)]
    draw.line(shape, fill=color, width=int(amount))
    y1 += amount
    y2 += amount

im.save("pre_diagonal.png")
colorimage = Image.open('pre_diagonal.png')
out = colorimage.rotate

Answer 1

You can do it by first generating an image of vertical lines like I showed you in my answer to your other question, rotating that by 45°, and then cropping it. To avoid having areas of black, you need to generate an initial image that is large enough for the cropping.

In this case that's simply a square image with sides the length of the hypotenuse (diagonal) of the final target image's size.

i.e.

Graphically, here's what I mean:

At any rate, here's the code that does it:

from math import hypot
from PIL import Image, ImageDraw
import random

IMG_WIDTH, IMG_HEIGHT = 1000, 1000
DIAG = round(hypot(IMG_WIDTH, IMG_HEIGHT))

img = Image.new('RGB', (DIAG, DIAG), (255, 255, 255))
draw = ImageDraw.Draw(img)
colors = [(255,0,255), (0,0,255)]
random.shuffle(colors)

length = len(colors)  # Number of lines.
line_width = DIAG / length  # Width of each.
difx = line_width / 2
x1, y1 = difx, 0
x2, y2 = difx, DIAG

for color in colors:
    endpoints = (x1, y1), (x2, y2)
    draw.line(endpoints, fill=color, width=round(line_width))
    x1 += line_width
    x2 += line_width

img = img.rotate(-45, resample=Image.Resampling.BICUBIC)
difx, dify = (DIAG-IMG_WIDTH) // 2, (DIAG-IMG_HEIGHT) // 2
img = img.crop((difx, dify, difx+IMG_WIDTH, dify+IMG_HEIGHT))
img.save('diagonal.png')
#img.show()

Here's the resulting image: